JSON Validator
Validate JSON instantly. Check syntax errors, formatting issues, and invalid JSON data directly in your browser.
{
"name": "John",
"age": 30
}How to validate JSON?
A JSON validator checks whether your text follows JSON syntax rules. Use this online JSON validator to confirm that objects, arrays, strings, numbers, and commas are written correctly before you use the data in an app, API request, or config file.
Validation runs entirely in your browser with no server upload, so you can check private JSON safely. When something is wrong, the JSON syntax checker points to the line and column so you can find JSON errors faster.
How to use this JSON checker
Paste JSON
Paste JSON text or upload a .json file. Validation starts as you type.
Click Validate
Results update as you type. Click Validate JSON to jump to the status.
Fix errors
Use the line and column details to repair syntax issues, then format or minify the valid result.
Need a smaller file after validation? Minify JSON. Prefer indented output? Format JSON.
JSON validation features
- Free JSON validator
- Instant validation
- JSON syntax error detection
- Shows where errors are (line, column, path)
- Works locally in browser
- No data upload
- Upload and check .json files
- Format and minify valid JSON
Invalid JSON example
Trailing commas are a common reason JSON is invalid. The JSON error checker highlights the problem so you can produce fixed JSON quickly.
{
"name": "John",
}{
"name": "John"
}JSON Validator vs JSON Formatter
| JSON Validator | JSON Formatter | |
|---|---|---|
| Main question | Is this JSON valid? | Can I read this JSON clearly? |
| Primary output | Valid / invalid plus error location | Indented, easier-to-read JSON |
| Best use | Finding and fixing syntax errors | Reviewing and editing structure |
| Where to start | Use this validator first | Format JSON once the input is valid |
Looking for differences between two documents instead? Compare JSON files side by side.
Frequently asked questions
What is a JSON validator?
A JSON validator is a tool that checks whether text follows JSON syntax rules. It tells you if the document is valid and helps you find syntax problems.
How do I validate JSON?
Paste your JSON into the editor or upload a .json file. This JSON validator tool checks the input instantly and shows whether it is valid. After it passes, you can pretty-print with JSON Formatter or shrink it with JSON Minify.
Why is my JSON invalid?
Common issues include trailing commas, missing quotes around keys, single quotes instead of double quotes, unescaped characters, and unmatched braces or brackets.
How do I check if JSON is valid?
Use an online JSON validator or JSON syntax checker. This page validates JSON as you type and reports the line and column when something is wrong. To compare two valid documents next, open JSON Compare.
Is this JSON validator free?
Yes. This free JSON validator runs in your browser with no account, no upload, and no sign-up.
Can I validate a JSON file?
Yes. Choose a .json file to check it on this device. Nothing is uploaded to a server.